Water-soluble esters of alkyl siliconic acids



Patented July 19, 1949 UNITE STATES WATER-SOLUBLE ESTERS OF ALKYL SILICONIC ACIDS David Xavier Klein, Andover. Mass., and Donovan Erb Kvalnes, Penns Grove, N. J., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 2, 1946, Serial No. 700,834

3 Claims.

This invention relates to water-soluble longuseful as water-repellency agents for textile fiber.

Other and further important objects of this invention will appear as the description proceeds.

According to my invention, the aforegoing objects are accomplished by reacting a silicon ester compound of the formula R-SHOCaHsh, wherein R is analkyl radical of from 12 to 24 carbon atoms, with an ethylene polyglycol of the general formula H'(OCzH4)n-OH, wherein n is a numeral not less. than 2, whereby the 002m radicals in the silicon ester become replaced by polyglycol radicals. When n=2 the molecular weight of the polyglycol is 106 and as 1: increases by vaults of 1 the molecular weight rises by units of 4 A common, commercial ethylene polyglycol is one having the unit OC2H4 repeated an average of 4 times and therefore corresponding to the formula HOC2H4.0C2H4.0C2H4.0C2H4.0H. Because its average molecular weight is in the vicinity of 200, it is commonly designated in the art as polyglycol200. However, polyglycols of longer chain may also be used for our invention, for instance polyglycol-300, 400 and --600.

The reaction is eilected by heating one mole oi. the long-chain alkyl-silicon triethoxide with'3 moles of the selected polyglycol, while continuously removing, as by distillation, the alcohol split off in the reaction. The resulting compound may be represented by the formula RSi(Q-OH) 3, wherein R is an albl radical of 12 to 24 carbon atoms, while Q is a polyglycol radical having a chain of from 2 to 12 OC2H4 units. It is characterized by solubility in water, which may be enhanced by adjusting the alkalinity of the mixture to a pH of 7.5 to 8.0, and has the useful quality a of being an active dispersing agent. For instance,

it is eflfective for producing oil-in-water type emulsions. I

Another outstanding and useful quality of the reaction product is its property of rendering textile fiber water-repellent, if the fiber is impregnated'with said aqueous solution, squeezed out of excess moisture, and then subjected to a heat treatment at a temperature between 100 and 150 C. Pres umably, during this latter baking step, the silicon ester hydrolyzes, splitting oil the polyglycol radicals, and changing the residue into a polymer of an alkyl-siliconic acid Whl monomeric formula is R-8l0.0H, wherein R the long-chain alkyl radical initially started wi- Without limiting our invention, the followi examples are given to illustrate our prel'err mode of operation. The parts indicated, clea1 may be varied to any optional magnitude solo as the same relative proportions are maintaim Example 1.Preparation of the silicon compou:

29.1 gm. of polyethylene-glycol-200 and 21 gm. of octadecyl-silicon-triethoxlde.

CmHsvSi (OCaHs) a were heated in a flask surmounted with Vigreaux column. Originally, the two componer were in separate layers. As the temperatu reached 200 C., a homogeneous solution resulte Heating was-continued between 200 and 300 1 while the ethyl alcohol was continuously remove when the head temperature on the colun dropped below 78 0., the heating was inte rupted and the product cooled down. 43 g! of a thick oil were obtained, which set to a sem solid gel on long standing. Its average molecull weight corresponded to the formula CIBHMSI (OCECHzOCI-IzCHz OCHaCHzOCHzCHzOH This material is soluble in water to give slightly cloudy solution, which has enhanc4 stability it an adjustment of alkalinity is ma: by means of NaHCOa to pH 7.5 to 8.0.

Example Z.Use as a dispersing agent 50 cc. 01 a 4% solution of octadecyl-silicon-t (glycol-200) ester in water, containing .3 gr NaHCOa, were warmed to 70 0., and 25 gm. 1 melted paraflln wax at 70 C. were added to while stirring vigorously with a malted-mil mixer.

A good dispersion was obtained. 10 gm. 1 this dispersion were made up to 200 cc. with wate and a piece of olive drab dyed poplin treated 1 it. After drying it was dipped in dilute oxal acid solution, and then re-drled. A. watei repellency of-90+ was obtained.

- Example 3.--Use as a water-repellent per se 12 gm. of the octadecyl-silicon-tri(glycol-200 ester were dissolved in 240 cc. of water. 90 gn of poplin fabric were wet out thoroughly in tli solution and squeezed out. The wet weight c the squeezed fabric was 167 gm.. indicating 55 pick up of '17 gm. of solution. This correspond 85 gm. of the ester, which in turn is equivalent .41 gm. of the monomer (C1aH31--SiO.OH), n calculated on the molecular weight ratio 60:314. The fabric was then steamed for 1 then immersed in a aqueous glycolic solution (to insure complete hydrolysis of ester), and dried at 100 0. Its initial water llency was 100. The final weight of the ma- L] was 91.4, indicating an actual pick-up of :m. of the polymer. After 3 washes a waterllency of 70 still obtained.

will be understood that the above examples merely illustrative and that the details of edure may be varied widely within the skill iose engaged in this art. 1e uses and advantages of our invention will be readily appreciated. The novel products his invention constitute valuable surface 'e agents of a transitory type which possess, hydrolysis, a high contact angle for the vater-product interface, thus producing a 1y water-repellent surface from a soluble arial. While in the soluble stage, they posexcellent emulsification properties. a claim as our invention:

A hydrolyzable, water-soluble ester of an I trihydroxy-silane, said ester being charrized by surface-active properties and being inable by reacting a silicon compound of the lula RSi-(OC2H'5) 3, wherein R is an alkyl :al of at least 12 carbon atoms, with a polylene glycol having the unit OCH2.CH2 reed in a chain from 2 to 12 times, the molal i of polyethylene glycol to silicon compound g substantially 3:1.

4 2. A hydrolyzable, water-soluble ester of octadecyl trihydroxy-silane, said ester being characterized by surface-active properties and being obtainable by reacting octadecyl-sillcon-triethoxide with a polyethylene glycol having the unit OCH2.CH: repeated in a chain from 2 to 12 times, the molal ratio of polyethylene glycol to octadecyl-sillcon-triethoxide being substantially 3:1.

3. A hydrolyzable, water-soluble ester of octadecyl 'trihydroxy-silane, said ester being characterizedby surface-active properties and being obtainable by heating 1 mole of octadecyl-silicontriethoxlde with substantially 3 moles of tetraethylene glycol and continuously removing the alcohol split on in the reaction.

DAVID XAVIER KLEIN. DONOVAN ERB KVALNES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTS Number Name Date 1,178,731 Knorr Apr. 11, 1916 2,027,931 Ray Jan. 14, 1936 2,048,799 Lawson July 28, 1936 2,349,338 Clapsadle May 23, 1944 2,386,793 Hanford Oct. 16, 1945 OTHER REFERENCES Rochow: Introduction to the Chemistry of the Silicones, 1947, page 122, Wiley 8: Sons, New York. 

